Rubber modified aromatic vinyl copolymer resins such as acrylonitrile-butadiene-styrene (ABS) resins can have excellent mold processability, physical properties such as impact strength, and appearance and have accordingly been widely used in the production of many electric or electronic goods such as automobile interiors, office equipment, displays and the like. Rubber modified aromatic vinyl copolymer resins, however, can have limited flame retardancy and thus can have limited use in the production of heat-emitting products such as computers and facsimile machines and high voltage equipment.
An exemplary method for providing rubber modified aromatic vinyl copolymer resins with desirable flame retardancy is to employ a flame retardant. In general, there are two types of flame retardants, halogenated flame retardants and non-halogenated flame retardants.
There are two important halogenated flame retardants, chlorinated flame retardants and brominated flame retardants. Chlorinated flame retardants are not typically desirable because they can cause corrosion on manufacturing equipment. The use of brominated flame retardants is regulated due to environmental contamination.
Accordingly, various non-halogenated flame retardants have been developed for use in rubber modified aromatic vinyl copolymer resins. However, the non-halogenated flame retardants typically cannot meet strict flame retardancy regulations and/or provide desired heat resistance.
Among the flame retardants, brominated flame retardants has been a target for improving flame retardancy of rubber modified aromatic vinyl copolymer resins because brominated flame retardants can provide excellent flame retardancy as well as heat resistance even when used in a small amount. As molded articles including using the rubber modified aromatic vinyl copolymer resin become larger and more complicated, yet also thinner, it is important to impart excellent flame retardancy to the thin molded articles or thin films. Brominated flame retardants can provide such thin molded articles or thin films with desirable flame retardancy.
Brominated flame retardants include tetrabromobisphenol A, brominated epoxy compounds, 2, 4, 6-tris(2, 4, 6-tribromophenoxy)-1, 3, 5-triazine (TTPT), decabromodiphenyl ethane and the like. Tetrabromobisphenol A has good flowability, but poor impact strength and heat stability. Brominated epoxy compounds have better heat stability than tetrabromobisphenol A, but poor impact strength. To overcome the poor impact strength of brominated epoxy compounds, more rubber should be used. TTPT can improve impact strength, but can cause a problem on the surface of the molded articles by generating gas due to poor heat stability. Decabromodiphenyl ethane can have excellent heat stability, but poor impact strength because of poor compatibility with ABS resin.